Optical tuning of light emitting semiconductor junctions

Abstract

Light emitting semiconductor junctions are disclosed. An exemplary light emitting junction has a first electrical contact coupled to a first side of the junction. The exemplary junction also has a second electrical contact coupled to a second side of the junction. The exemplary junction also has a region of set straining material that exerts a strain on the junction and alters both: (i) an optical polarization, and (ii) an emission wavelength of the junction. The region of set straining material is not on a current path between said first electrical contact and said second electrical contact. The region of set straining material covers a third side and a fourth side of the light emitting junction along a cross section of the light emitting junction. The light emitting semiconductor junction device comprises a three-five alloy.

What is claimed is: 
     
       1. A process for fabricating a deep ultraviolet light emitting diode comprising:
 forming a homojunction of said light emitting diode; 
 testing an optical polarization of said light emitting diode; 
 testing an emission wavelength of said light emitting diode; 
 introducing a set strain to said light emitting diode after testing said optical polarization of said light emitting diode; and 
 packaging said light emitting diode after introducing said set strain. 
 
     
     
       2. The process of  claim 1 , further comprising:
 forming a passivation layer across a top surface of said light emitting diode; 
 wherein said passivation layer provides said set strain to said light emitting diode; and 
 said set strain is a biaxial strain. 
 
     
     
       3. The process of  claim 1 , wherein:
 said homojunction comprises aluminum; and 
 said homojunction is supported by a bulk substrate. 
 
     
     
       4. The process of  claim 1 , wherein:
 said set strain alters an emitted light propagation direction of said light emitting diode from a transverse magnetic direction to a transverse electric direction. 
 
     
     
       5. A process for calibrating a fabrication line for producing devices with light emitting semiconductor junctions, comprising:
 selecting a primary composition proportion for a group three material in a three five semiconductor material; 
 forming a light emitting semiconductor junction using said semiconductor material; 
 obtaining a first measurement of an optical polarization and emission wavelength of light generated by said light emitting semiconductor junction; 
 straining said light emitting semiconductor junction using a wafer process to target a desired emission wavelength and a desired optical polarization; and 
 reselecting said primary composition proportion if said straining cannot achieve said desired emission wavelength and said desired optical polarization. 
 
     
     
       6. The process of  claim 5 , wherein:
 said straining induces a tensile strain if said first measurement determines that said optical polarization is transverse electric; and 
 said light emitting semiconductor junction produces light for a light emitting diode. 
 
     
     
       7. The process of  claim 5 , wherein:
 said straining induces a compressive strain if said first measurement determines that said optical polarization is transverse magnetic; and 
 said light emitting semiconductor junction produces light for a semiconductor laser. 
 
     
     
       8. The process of  claim 5 , wherein:
 said straining induces a tensile strain if said first measurement determines that said emission wavelength is less than said desired emission wavelength; and 
 said straining induces a compressive strain if said first measurement determines that said emission wavelength is more than said desired emission wavelength. 
 
     
     
       9. The process of  claim 5 , further comprising:
 obtaining a second measurement of said emission wavelength after said straining has induced a maximum acceptable strain of said light emitting semiconductor junction; and 
 wherein:
 said reselecting increases said primary composition proportion if said second measurement of said emission wavelength is less than said desired emission wavelength; and 
 said reselecting decreases said primary composition proportion if said second measurement of said emission wavelength is greater than said desired emission wavelength. 
 
 
     
     
       10. The process of  claim 5 , wherein
 said group three material is aluminum. 
 
     
     
       11. The process of  claim 10 , wherein:
 said semiconductor material is a ternary group-three nitride alloy; and 
 said ternary group-three nitride alloy comprises gallium. 
 
     
     
       12. The process of  claim 5 , wherein said straining comprises
 conducting said wafer process on a wafer after obtaining said first measurement and before singulating dies from said wafer; and 
 wherein said wafer comprises said light emitting semiconductor junction. 
 
     
     
       13. The process of  claim 12 , wherein said wafer processing step comprises
 forming a passivation layer on a top surface of said wafer. 
 
     
     
       14. The process of  claim 12 , wherein said wafer process comprises:
 etching into a top surface of said wafer to form a set of excavated regions in said wafer; and 
 forming a set of pillars in said excavated regions, said pillars comprising a straining material. 
 
     
     
       15. A process for fabricating a light emitting semiconductor junction comprising:
 forming a set of light emitting semiconductor junctions on a lot of wafers using a semiconductor material, said light emitting semiconductor junction being in said set of light emitting semiconductor junctions and on a wafer in said lot of wafers, and said semiconductor material comprising a group three material and a group five material; 
 measuring an optical polarization and an emission wavelength of light generated by said light emitting semiconductor junction to obtain a measurement; 
 straining said light emitting semiconductor junction using a wafer process conducted on said wafer after said measuring of said optical polarization and said emission wavelength of light generated by said light emitting semiconductor junction, said wafer process being conducted before singulating a die from said wafer; 
 remeasuring said optical polarization and said emission wavelength of light generated by said light emitting semiconductor junction after straining said light emitting semiconductor junction to obtain a second measurement; and 
 straining a second light emitting semiconductor junction from said set of light emitting semiconductor junction on a second wafer from said lot of wafers based on said measurement, a desired optical polarization and a desired emission wavelength. 
 
     
     
       16. The process of  claim 15 , wherein:
 said group three material is aluminum; and 
 said semiconductor material is ternary group-three nitride alloy. 
 
     
     
       17. The process of  claim 15 , wherein:
 said wafer process is a variant wafer process; and 
 said remeasuring collects a plurality of different data points based on said variant wafer process. 
 
     
     
       18. The process of  claim 15 , wherein said wafer process comprises
 forming a passivation layer on a top surface of said wafer. 
 
     
     
       19. The process of  claim 18 , wherein:
 said measurement indicates that said optical polarization of light generated by said light emitting semiconductor junction is a transverse magnetic polarization; 
 said light emitting semiconductor junction is used for a semiconductor laser; and 
 said passivation layer introduces a tensile strain to said second wafer. 
 
     
     
       20. The process of  claim 18 , wherein:
 said measurement indicates that said optical polarization of light generated by said light emitting semiconductor junction is a transverse electric polarization; 
 said light emitting semiconductor junction is used for a light emitting diode; and 
 said passivation layer introduces a compressive strain to said second wafer.